Method of making synthetic fiber rope and rope produced thereby



Aprll 7, 1959 R. T. STARR 2,880,568

METHOD OF MAKING SYNTHETIC FIBER ROPE AND ROPE PRODUCED THEREBY' Filed Sept. 9. 1953 NYLON YARN 5 1* WJQTER NYLON YARN illl FIGAr.

INVENTOR. RAYMOND T. STARR BYQQ I Q t $315 ATTORNEYS United tates Patent This invention relates to an improved stranded rope structure formed of synthetic fibers and particularly concerns nylon rope and the method of making the same.

in the manufacture of rope of synthetic fibers, such as nylon, one of the problems encountered is the tendency o f'yarns and strands in the rope to become dislocated or Fig. 1 is a diagrammatical illustration of an apparatus for immersing yarns into a hot water bath;

Fig. 2 is aview similar to Fig. 1 illustrating an appa ratus for immersing yams into a water alcohol solution of liquid nylon; I o 7 Fig. 3 is a diagrammatic illustration of a method of forming the rope of this invention;

Fig. 4 is a view similar to Fig. -1 illustrating an ap'pa rat'us for immersing the rope into 'a hot water bath; and

Fig. 5 is a diagrammatic illustration of a coiled rope undergoing treatment by steam under pressure.

In accordance with the invention, yarns 10 of synthetic fiber, such as ny-lon, are pre-set by being immersed in a hot water bath 11 which may be boiling water, as is illustrated in Fig. 1. Subjecting the yarns to the hot water effects a prel-iminaryfshr-inkage of the fibers to re= displaced forming kinks or hockle's in the rope.- To a large extent this, and the tendency of synthetic fibers to fray have been overcome by following the teachings of Dodge et al-. Patent No. 2,343,892, issued March 14, 1944. However, in large sizes of ropes, for example those exceeding seven inches in circumference, and particularly large hawsers used in deep-sea towing, rope of syn thetic fibers manufactured according to the method of the aforementioned Dodge et al.- patent has become un usable in a very short period of time. Kinks and hockles formed in a rope with a nine inch circumference have been so numerous and so severe that the hawser could not be repaired and returned to service.

.It is, therefore, a major object of this invention to provide a stranded rope structure of synthetic fiber which is more stable and durable; Another object of the invention is to provide a method of making a stranded -rope of synthetic fiber, such as nylon, which is particularly applicable to large sizes of ropes and produces a more stable and durable finished product.

More particularly, an object of the invention is .to provide a rope of large size which is harder and firmer than ropes of synthetic fiber heretofore produced and which retains the hardness and firmness when wet so the likelihood of the formation of kinks and hockles in individual strands of the rope is substantially reduced if not altogether eliminated.

In the attainment of these objects, one feature of the invention resides in the inclusion or the method 'of making a rope of synthetic fibers of the step of subjecting the to a hot liquid or hot water bath treatment before fiber in the yarns and then combining the coated yarns with other yarns and then twisting the coated yarns with other pre-set yarns to form 'a strand having coated yarns uniformly distributed throughout "the strand.

According to "another feature of the invention, a more complete setting of the large rope structure is accomplished by first subjecting the rope to a hot liquid or hot water bath to initially set the yarns and then subject the rope to a steam treatment for completing a more permanent, durable and harder set of the elements of the rope.

Withv these and other objects in view, the invention consists in certain details of construction and combinations and arrangement of parts, all as will hereinafter be more fully described, and the novel features thereof particularly pointed out in the appended claims.

In theaceompanying drawing:

duce the effect of water upon the completed rope. Some of the yarns 10, after being pre-set in bath 11, are stiff ened by coating them with a coating of compatible synthetic material. In the case of nylon fiber, the yarns 10 are immersed in and passed through an alcohol-water .solution of nylon 13 to partially impregnate the yarns and form a thin film or coating of nylon.

The coated yarns 14, .prior to drying, are twisted together with other pre-set yarns 12 into strands 16, so the coated yarns are uniformly distributed throughout the strand and surrounding yarns adhere somewhat to the coated yarns as the liquid coating, dries. A plurality of these strands 16 are then twisted into a rope 18. Upon drying,- the coated yarns become stiffer and impart a stiffening or hardening effect-to the rope structure.

Best results are achieved when the coated yarns are evenly dispersed throughout the cross-section of the rope. Ithas been found that strands having from 5% to 25% coated or stiffened yarns form ropes which have the desired characteristics, with particularly good resutls ob tained where the strands include approximately 10% coated nylon yams.

7 After strands 16 are twisted into a stranded rope 18, the entire rope is immersed into a hot water bath 20 as illustrated in Fig. 4. For best results, this water is boib ing and each increment of the rope remains immersed for a period of about twenty minutes. This partially sets the yarns and strands in the ropestructure and effects a ,p1- shrinking of the syntheti yanm 2 this hot water treatment, the rope may be formed into a coil 22 and placed in an autoclave 24 (Fig. 5) and subjected to steam under a pressure of 15 to 20 lbs. pe'r square inch for 1 to 4 hours. i

While it is recognized that steam treatment of the synthetic rope effects a more complete setting or" the rope structure and thereby increases the hardness or firmness of the rope, there are of course inherent difficulties in providing a continuous process for the steam treatment are rope several hundred feet long. In the past, efforts have been made to coil the ropefand effect a setting by subjecting the coiled rope to steam under pressure. This has been unsatisfactory because the shrinkage of the synthetic yarns, When subjected to the steam under ressure, has caused the convolutions of the coil to contract upon themselves and inflict such damage upon the rope that it is unsalable. By first subjecting the completed rope to the boiling water treatment and then coiling the rope, the preliminary shrinkage of the rope during the water treatment is sufiicient to avoid the excessive shrinkage heretofore present in steam treatment of the synthetic rope structure so the steam treatment of the coil effects a more complete setting of the rope into a harder-or firmer structure without damaging the rope due to shrinkage of the convolutions of the coil. i

A nine inch towing rope was manufactured according to the method heretofore described and placed in service iatented Apr. 7, 1959 i ass eea as a replacement for a similar nine inch nylon rope which i had become so kinked and snarled within a short time as to be useless. The replacement rope, which was manufactured according to the method of this invention, has been giving excellent service in deep-sea towing operations for a period of several months and indications are that it will continue to afford satisfactory service indefinitely because the synthetic yarns show little sign of wear and, of course, will not decay due to the action of sea water, etc. Even though this particular nine-inch nylon rope was subjected to an unusually severe test in an accident, damaged portions of the rope were easily repaired and the rope returned to service where it has continued to perform satisfactorily.

Having described my invention, what I claim is:

1. The method of forming a stranded rope structure of synthetic fiber which comprises twisting a plurality of synthetic yarns into strands, twisting a plurality of said strands into a rope,-immersing said rope in a heated fluid, forming said rope into a coil, then subjecting said coiled rope to steam under pressure, and cooling the rope to set the synthetic fiber in twisted relation in the rope.

2. The method of forming a stranded rope structure of synthetic fiber-which comprises immersing synthetic yarns in aheated fluid, twisting a plurality of said yarns into strands, twisting a plurality of said strands into arope, immersing said rope in a heated fluid, subjecting the rope to steam under pressure, and cooling the rope to set the synthetic fiber in twisted relation in the rope. I 3. The method of forminga-stranded rope structure of synthetic fiber which comprises coating synthetic yarns with synthetic material compatible with the synthetic fiber, twisting the coated yarns with uncoated yarns into strands, twisting a plurality of said strands into a rope, immersing the rope in a heated fluid, forming the rope into a coil, then subjecting the rope to steam under pressure, and cooling the rope to set the synthetic fiber in twisted relation in the rope.

4. The method'of forming a stranded rope structure of synthetic fiber which comprises immersing synthetic yarns in a heated fluid, coating the synthetic yarns with a synthetic material compatible with the synthetic fiber, twisting the coated yarns with a larger number of uncoated yarns into strands, twisting a plurality of said strands into a rope, subjecting the rope to steam under pressure, and cooling the rope to set the synthetic fiber in twisted relation in the rope.

5. The method of forming a stranded rope structure of synthetic fiber which comprises immersing synthetic,

yarns in a heated fluid, coating a number of the synthetic yarns with a synthetic material compatible with the synthetic fibers, twisting the coated yarns with a larger number of uncoated yarns into strands, twisting a plurality of said strands into a rope, immersing the rope in a-heated fluid, subjecting the rope to steam under pressure, and cooling the rope to set the synthetic fiber in twisted relation in the rope.

6. The method of forming a stranded rope structure of nylon yarns which comprises coating the nylon yarns with liquid nylon, twisting the coated yarns with uncoated 7. The method of forming a stranded rope structure of nylon yarns which comprises immersing the nylon yarns in hot water, coating :a number of the nylon yarns with liquid nylon, twisting the coated yarns with the uncoated yarns into strands, twisting a plurality of said strands into a rope, immersing the rope in hot Water, and then cooling the rope to'setsaid nylon yarns in twisted relation. 1

8. The method of forming a stranded rope structure of nylon yarns which comprises coating nylon yarns with a liquid nylon, twisting the coated yarns with uncoated yarns into strands, twisting a plurality of said strands into a rope, immersing the rope in hot water, forming the rope into a coil, subjecting the coiled rope to steam under pressure, and cooling the rope to set said yarns in twisted relation.

9. The method of forming a stranded rope structure of nylonyarns which comprises immersing the nylon yarns in aheated liquid bath, coating 21 number of the nylon yarns with liquid nylon, twisting the coated yarns with the uncoated yarns into strands, twisting a plurality of said strands into a rope, immersing the rope' in hot water, subjecting the rope to steam under pressure, and cooling the rope to se't'said yarns' in twisted relation. 1

4 10. The method of forming a stranded rope structure of nylon yarns which comprises immersing the yarns in hot water, twisting said yarns into strands, twisting a plurality ,of strands intoa rope, immersing the rope in hot water, forming the rope into a coil, subjecting the coiled rope to steam under pressure, and cooling the rope to set the nylon yarns in twisted relation.

11. A stranded rope structure of synthetic fiber formed in accordance with the method defined in claim 1.

12. A stranded rope structure of synthetic fiber formed in accordance with the method defined in claim 2.

13. A-stranded rope structure of nylon yarns formed in accordance with the method defined in claim 3.

14. A stranded rope structure ofnylon yarns formed in accordance with the method defined in claim 4. l

15. A stranded rope structure of nylon yarns formed in accordance with the method defined in claim 5.

16. A-stranded rope structure of nylon yarns formed in accordance with the method defined in claim 6.

17. A stranded rope structure of nylon yarns formed in accordance with the method defined in claim 7. 3

18. A stranded rope structure of nylon yarns formed in accordance with the method defined in claim 8.

19. A stranded rope structure of nylon yarns formed in accordance with the method defined in claim 9. i

20. A stranded rope structure of nylon yarns formed in accordance with the method defined in claim 10.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Nylon Technical Manual, pages 6-4.01 to 6-4.03, E. I. du Pont de Nemours & Co., Inc., Wilmington, Del. 

